This disclosure relates generally to machine tools, and specifically to punch assemblies for metal working. In particular, the disclosure relates to punch tool assemblies suitable for use in punch press machines, including, but not limited to, high speed punch presses used in fabrication and manufacturing.
Industrial tooling machines including turret and rail-type punch presses are widely used in the fabrication of sheet metal workpieces and other sheet components (e.g., metal, plastic, leather, etc.). Automated punch presses are commonly employed in manufacturing applications, including single and multi-station presses, press brakes, sheet and coil feed systems, rail-type machine tool systems, and other fabrication equipment adapted for pressing, bending and punching sheet metal components, used to fabricate sheet metal and other workpieces into a wide range of useful products.
Punch presses in particular have found wide use in sheet metal hole punching and forming applications. Turret presses typically have an upper and lower turret sections that hold a series of punches and dies, spaced circumferentially at different locations around the periphery of the turret. The turret press can then be rotated about a vertical axis to bring a desired punch and die set into vertical alignment with a work station, or to bring a series of different punch and die sets sequentially into alignment for performing a series of different pressing operations. Rail-type and single-tool punch presses are also widely used.
The workpiece itself is commonly formed of a piece of sheet metal, disposed between selected punch and die combinations. The punches can be operated under computer control, when the selected punch and die assemblies are aligned across the workpiece. The punch is driven through the workpiece and into the die, forming a hole or other desired feature.
Punch systems typically include an outer punch guide with a punch member reciprocating in a longitudinal bore, or a punch ram assembly with a bushing to hold the punch. The punch itself typically includes a shank or body portion and a punch point or other forming tool on the working end, facing the sheet metal component or workpiece. The punch point engages the workpiece in the punch stroke, forming a hole by driving a slug out of the workpiece metal and through the die. A return spring or punch clamp can be used to urge the punch back into its original position, in a stripping action following the punch stroke.
A high number of repeated strokes are typical in automated machine tool applications. The punch point may thus become worn, and require sharpening or replacement. There is a constant need to make the replacement process less complex and more efficient, with less downtime and reduced replacement cost.